1. Field of the Invention
The present invention relates generally to wireless sensor networks, and more specifically to scheduling data transmissions and providing failed node recovery in a wireless sensor network.
2. Discussion of the Related Art
Wireless sensor networks have become popular in the recent years for forming a wireless network of various types of sensors that monitor conditions such as range, distance, temperature, sound, vibration, pressure, motion, or pollutants. Wireless sensor networks have been implemented in defense applications, environmental monitoring, habitat monitoring, surveillance and security, industrial/commercial inventory tracking, process monitoring and disaster recovery. Some wireless sensor networks are deployed as multi-hop “ad-hoc” networks. Typical ad-hoc networks include network nodes that are deployed with little or no existing infrastructure and form a network dynamically. These types of networks, typically, have limited capabilities for adapting to a failed node. In addition, conventional sensor networks typically implement omni-directional antennas for communication by the various nodes.
Various aspects of wireless sensor networks, including medium access control (MAC), task scheduling, and networking protocols, have been previously presented. Examples of such discussions can be found in U.S. Pat. Nos. 7,082,117, 7,075,476, 7,054,126, 6,986,161, 6,975,613, 6,807,165, 6,754,188, and 6,208,247.
In addition, wireless sensors and wireless sensor networks are described in various publications. Examples of such publications include various University of California Berkeley's projects such as Smart Dust, NEST, UCLA's NIMS and WINS projects, and the University of Florida's Atlas project. Commercial companies producing various types of sensor networks include Sensoria, Dust networks, Ember Networks, Crossbow technologies, Pervasa and Sensicast Systems.